This invention relates to an endless loop, being a flat toroidal article of manufacture, comprising a core consisting essentially of at least one skein, and a protective substantially toroidally shaped covering consisting essentially of hose fabric, having a central loop axis longitudinally extending therein, and loosely surrounding the core. The hose fabric has, as usual, a warp threading and a weft threading.
Such endless loops or torus-like bodies have been described, for instance, in German Offenlegungsschrift (published patent application) No. 2,129,837, in Canadian Pat. No. 953,882 and in European patent application No. 0032749.
It is a feature of such known torus-shaped bodies that the skein constituting the core in the body fills the cross sectional area of the toroidal covering hose only by about 50 to 70%, whereby the core remains freely displaceable in the interior of the annular body in longitudinal direction as well as transverse thereto. The individual windings of the core are not fixed in relation to the protective annular hose or with regard to each other. The individual turns of the skein can, therefore, move relative to one another when under load and thereby attain, due to the load, equal lengths, so that an overloading of an individual thread winding is avoided. The protective annular body is manufactured as a hose fabric or tissue. Technically, a textile hose fabric is a two-layer fabric consisting of an upper fabric and a lower fabric, wherein the mutual connection between the upper and the lower fabric is only present at the longitudinal marginal edges, whereby a hollow hose interior is formed between the two opposite marginal edges. Being manufactured in this manner, the finished protective hose has the aspect of a strip or band-shaped body.
The manufacture of the initially described endless loop or torus-shaped body disclosed in German Offenlegungsschrift No. 2,129,837 and Canadian Pat. No. 953,882 has been described more in detail in European patent application Publication No. 0032,749 which description is hereby incorporated by reference.
After manufacturing the finished torus-shaped endless loop article, which is achieved by introducing the skein constituting the loop core into the protective toroidal covering, the latter assumes a somewhat slightly inflated configuration as compared with the original flat belt-shape, and then has a cross sectional contour which can be described as a flat oval. One of the two ends of the protective covering is then inserted into the other, and the two ends are then connected with each other preferably by sewing them together. Even after this step, the protective covering is of somewhat greater length, about the entire circumference of the endless loop covering, than the core constituted by the skein. This excess of length of the protective covering above the length of the core serves to guarantee that, when under load, that load will be absorbed exclusively by the core, i.e. by the skein, so that the protective covering is not subjected to any tensile stress. This ensures that, in the loaded article, the protective covering, being under no tensile stress, therefore will not tear; tearing would cause it to lose its protective and enveloping functions with regard to the core. This excess of length causes, in particular on the side of the protective covering facing toward the load, a slight folding of the covering which undesirably affects the handling of the article, and renders a further processing thereof, more difficult; it also causes a greater wear of the protective covering in the region where these folds are formed.